Pop-up sprinklers in a variety of styles have for many years been used to irrigate ground-cover plantings. Sprinklers of this type have a nozzle or spray head mounted at the upper end of a riser which is movably mounted on a housing or sprinkler body buried in the ground and connected to a subsurface water line. When the water is turned on, the riser elevates to position the head above surrounding plantings to insure proper distribution of the irrigation water.
Pop-up sprinklers are advantageous in that the riser and head are retracted to the soil level when watering is not taking place. This low-profile aspect of the sprinkler makes the sprinkler essentially invisible beneath the overlying planting to minimize the risk of sprinkler-head theft or other vandalism, and the possibility of passerbys striking or tripping on the head, these problems being common with sprinkler heads mounted on fixed nipples of six to twelve inch height.
Most prior-art sprinklers, however, have used a relatively small elevation (perhaps a few inches) of the head, and those designs with larger elevation capabilities have been unreliable due to jamming or clogging of the riser caused by ingested dirt or sand within the sprinkler. This problem is particularly acute in sprinklers which use line pressure to flush the housing interior during riser movement, because jamming of or interference with the riser at an intermediate position results in flooding of the area around the sprinkler when the flush water flows at line pressure around the outside of the riser.
The sprinkler of this invention provides excellent elevation (typically about 12 inches) of the head above the retracted position, and minimizes the risk of jamming by a novel cup seal arrangement and riser wiper system. Importantly, the use of line-pressure water is avoided for internal flushing during riser movement, and flushing can instead be done with static water which is trapped in a cavity within the sprinkler. The new sprinkler is also fitted with a relatively high side inlet to eliminate the need for deep burial of the water supply line, and the inlet is fitted with a rotatable union nut which enables quick and simple connection of the sprinkler to the supply line without rotation of the entire sprinkler assembly. Burial of the side-entry inlet connection has the added advantage of preventing theft by a simple unscrewing manipulation at the surface.